This invention relates to underwater viewing systems used to allow, for example, a diver or video system to see through muddy or otherwise turbid water. The invention may also find utility for use in other visibility impaired fluids, such as smoke, oils and foaming liquids.
In turbid water a viewing system typically sees nothing but a brown haze of silt, oil or mud. If the turbidity is heavy or concentrated enough, then no illumination can get through either, a condition which the diving community calls black water (BW). BW can be ubiquitous in such places as a sea floor experiencing storm action, the roiling bottom of the Mississippi River, industrial vats or working conduits transferring opaque liquid, opaque slurries, smoke or other visibility impaired gasses, foaming or sudsy liquids, etc. BW can also be caused simply by a diver's movement or a remotely operated vehicle's churning up the silted sea bottom in the normal course of doing work on the bottom. For the diver, his or her only other input is the sense of touch which leaves a lot to be desired when wearing gloves in cold or contaminated water. The quality of work may suffer and production may be slowed. For a system such as a remotely operated vehicle (ROV), which relies solely on a video camera, there is no alternative sense but SONAR which does not have the color sense and the close-up resolution of video.
The simplest method of seeing through turbidity is to use a transparent hydraulic system to displace the turbidity with an illuminated free jet stream of clear water through which, for example, a diver or video system can view the work.
However, one must be careful how the jet is designed because a simple jet stream played into a stationary fluid will break up into turbulence almost immediately. Turbulence is a very efficient mixing regime so the clear water jet would almost immediately be mixed with the surrounding black water, thus destroying the clear column.